Specna Arms ESA 2.1 spring guide and steel ball bearing part designed for airsoft guns or frames equipped with Specna Arms' ESA2.1™ system.
The ESA 2.1 spring guide has a smaller diameter than the ESA 2.0 spring guides and is not cross-compatible. In ESA 2.1 compatible frames, the thickness of the metal around the spring guide has been increased, which provides the frames with greater durability.